On Thu, 24 Oct 2024 17:12:22 +0100,
Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> [1 <text/plain; us-ascii (7bit)>]
> On Wed, Oct 09, 2024 at 07:36:03PM +0100, Marc Zyngier wrote:
> > As there is very little ordering in the KVM API, userspace can
> > instanciate a half-baked GIC (missing its memory map, for example)
> > at almost any time.
>
> The vgic_init selftest has started failing in mainline on multiple
> platforms, with a bisect pointing at this patch which is present there
> as commit df5fd75ee305cb5. The test reports:
>
> # selftests: kvm: vgic_init
> # Random seed: 0x6b8b4567
> # Running GIC_v3 tests.
> # ==== Test Assertion Failure ====
> # lib/kvm_util.c:724: false
> # pid=1947 tid=1947 errno=5 - Input/output error
> # 1 0x0000000000404edb: __vm_mem_region_delete at kvm_util.c:724 (discriminator 5)
> # 2 0x0000000000405d0b: kvm_vm_free at kvm_util.c:762 (discriminator 12)
> # 3 0x0000000000402d5f: vm_gic_destroy at vgic_init.c:101
> # 4 (inlined by) test_vcpus_then_vgic at vgic_init.c:368
> # 5 (inlined by) run_tests at vgic_init.c:720
> # 6 0x0000000000401a6f: main at vgic_init.c:748
> # 7 0x0000ffffa7b37543: ?? ??:0
> # 8 0x0000ffffa7b37617: ?? ??:0
> # 9 0x0000000000401b6f: _start at ??:?
> # KVM killed/bugged the VM, check the kernel log for clues
> not ok 10 selftests: kvm: vgic_init # exit=254
>
> which does rather look like a test bug rather than a problem in the
> change itself.
Well, the test tries to do braindead things, and then the test
infrastructure seems surprised that KVM tells it to bugger off...
I can paper over it with this (see below), but frankly, someone who
actually cares about this crap should take a look (and ownership).
M.
diff --git a/tools/testing/selftests/kvm/aarch64/vgic_init.c b/tools/testing/selftests/kvm/aarch64/vgic_init.c
index b3b5fb0ff0a9..60b076ae85ea 100644
--- a/tools/testing/selftests/kvm/aarch64/vgic_init.c
+++ b/tools/testing/selftests/kvm/aarch64/vgic_init.c
@@ -742,6 +742,8 @@ int main(int ac, char **av)
pa_bits = vm_guest_mode_params[VM_MODE_DEFAULT].pa_bits;
max_phys_size = 1ULL << pa_bits;
+ allow_ioctl_returning_eio = true;
+
ret = test_kvm_device(KVM_DEV_TYPE_ARM_VGIC_V3);
if (!ret) {
pr_info("Running GIC_v3 tests.\n");
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index bc7c242480d6..988c68a77ce3 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -298,6 +298,8 @@ static __always_inline void static_assert_is_vm(struct kvm_vm *vm) { }
kvm_do_ioctl((vm)->fd, cmd, arg); \
})
+extern bool allow_ioctl_returning_eio;
+
/*
* Assert that a VM or vCPU ioctl() succeeded, with extra magic to detect if
* the ioctl() failed because KVM killed/bugged the VM. To detect a dead VM,
@@ -313,6 +315,8 @@ do { \
static_assert_is_vm(vm); \
\
if (cond) \
+ break; \
+ if (errno == EIO && allow_ioctl_returning_eio) \
break; \
\
if (errno == EIO && \
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index a2b7df5f1d39..d9834421ab12 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -25,6 +25,8 @@ static uint32_t last_guest_seed;
static int vcpu_mmap_sz(void);
+bool allow_ioctl_returning_eio = false;
+
int open_path_or_exit(const char *path, int flags)
{
int fd;
--
Without deviation from the norm, progress is not possible.
